There are MANY keyboards that produce the Hammond/Leslie sound and also there are also some that provide synth (they all pretty much do MIDI). What is your budget and what other features are you looking for other than B3/leslie and synth? Piano? horns? strings? electric pianos? Again, the list of keyboards can be fairly extensive; so understanding your needs, budget, weight requirements would be a big help.
Check these: Nord Electro 3; Roland VR09, Kurzweil PC3K series, Casio WXP1, Hammond XK series, Hammond SK series, and many others. You can also buy a synth and run a Roland VK-8m (organ/leslie module) through MIDI. So to steer you in the right direction, answering the questions above including budget really helps us to help you. Also, you could perhaps go the other way, meaning a keyboard that is B3/leslie centric and purchase a synth module run through MIDI...